Friction brake spiral balance



Nov. 7, 1961 A. w. GRISWOLD FRICTION BRAKE SPIRAL BALANCE Filed April 15, 1959 +1 6 a 3 87. 8 9 323 2 4343s, 2 L. e i R 4 Q XLN mmk mwgf 4 3 267 I III/ Q, 5 5 4 IA/A AA 7 M 46122 M 6 5nwfiump a 8 I M m w 5 (1, 4 \A 6 3 a w .TY3

ATTORNEYS 3,097,194 Patented Nov. 7, 1961 use 3,007,194 FRIQTION BRAKE SPIRAL BALANCE Augustus W. Griswold, Rochester, N.Y., assignor to Pullman Manufacturing Corporation, Rochester, N.Y., a corporation of New York Filed Apr. 15, 1959, Ser. No. 806,696 Claims. (Cl. 16-193) This invention relates to a device for holding at an adjusted position two parts that are mounted to undergo rectilinear relative movement. More particularly, the invention relates to a device that is specially designed and adapted for holding a window sash at an adjusted position in its frame.

One common sash balance comprises a heavy metal weight that is suspended from a rope that is run over a pulley and that is connected to the window sash. The weight is mounted to move up and down in the framing. In this type of balance, when the cord ages, it has a tendency to break, particularly when the window is raised so rapidly that the speed of the window exceeds the speed of the weight, so that the weight snaps the cord sharply when it reaches the end of its travel. Replacement of the cord, and other repairs on this type of sash balance, are difiicult because of the necessity for getting access to the weight and the cord, within the framing. Moreover, a window with a balance of this type sometimes gets out of adjustment, and it occasionally happens that such a window is moved to an open position by its balance weights, so that to keep the window closed, it must be locked.

One object of the present invention is to provide a simple device that is practical for holding at an adjusted position two parts that are mounted to undergo rectilinear relative movement. A more specific object of the invention is to provide a device of the character described that can be used to hold a window sash at an adjusted position in its frame.

Another object of the invention is to provide a relatively simple, practical device that will hold a window sash at an adjusted position in its frame against the weight of the window sash, but that will not offer any substantial resistance to closing of the window.

A related object of the invention is to provide a device of the character described that can be mounted in a space between a lateral face of the window sash and a confronting, spaced surface of the framing, for easy access for maintenance and adjustment.

Another object of the invention is to provide a device of the character described that can be adjusted easily, to be operative for holding in position windows of different weights.

Other objects of the invention will be apparent hereinafter from the specification and from the recital of the appended claims.

In the drawing:

FIG. 1 is a side elevation, partly broken away, of one side portion of a window sash and of its frame, with the window adjusted to a slightly opened position and with part of the frame removed to show a space between lateral face of the window sash and a confronting surface of the frame, and with a device for holding the window at any adjusted position disposed in that space, according to one embodiment of this invention;

FIG. 2 is a part section, part elevation, on an enlarged scale, of the one-way friction clutch that forms a part of my device, showing the shaft of the clutch turned 90 from the position shown in FIG. 1, and

FIG. 3 is a section taken on the line 3-3 of FIG. 2, looking in the direction of the arrows, with the location of the twisted rod shown by dotted lines.

Referring now to the drawing by numerals of reference, 11 denotes the base and 12 the riser of a window frame. A stud 13 is secured to the rear of the base 11 and riser 12, and a second stud 14 is secured to the front of the base 11 and riser 12, to provide between the two studs an upright channel. A window sash 16 is mounted between the rear stud 13 and the front stud 14, with one of its lateral edges projecting into this channel, and with the lateral face 17 of the window sash disposed in confronting and spaced relation to a face 18 of the riser 12.

According to our invention, a device for holding the window sash 16 at any adjusted position within its frame is mounted in the space between the confronting faces 17, 18. This device includes a one-way friction clutch 19 that is mounted to move with the window sash 16, a

elically twisted metal rod 20 that is connected at its lower end to the clutch 19, a guide bracket 21 that is formed with a narrow slot 22 through which the rod 20 is passed, and bearing means 15, mounted at the top of the window sash 16, in which the upper end of the rod 20 is journalled.

Referring now particularly to FIG. 2, the one-way clutch has a generally-cylindrical casing 23 that is staked at its lower end to a laterally extending strap 24. The strap 24 is formed with a pair of holes 25 through which screws 27 (FIG. 1) are passed to secure the strap 24 to the bottom of the window sash 16, to hold the casing 23 rigidly, in an upright position relative to the window sash. The casing 23 is formed within annular recess within which a washer 26 is disposed. The washer 26 is proportioned to engage the confronting surfaces 17, 18 (FIG. 1) and preferably is made from a plastic material, such as, for example, polytetrafluoroethylene, polyethylene, and the like.

The casing 23 is formed with a stepped diameter bore including a small diameter part 27, and intermediate diameter part 28, and a large diameter part 29, that are coaxial and that communicate with each other. The small diameter part 27 is threaded, and a machine screw 30, that is slotted at its lower end, as denoted at 32, to receive a screw driver, is engaged in this small diameter part 27 of the bore. The casing 23 is formed with a shoulder 33 intermediate the small diameter part '27 and the intermediate diameter part 28 of the bore. The screw 30 is formed with a slotted head 34- of enlarged diameter and a flange 35. In the extreme lower position of adjustment of the screw 3%, that is shown in FIG. 2, the flange 35 is seated on the shoulder 33.

A coil spring 36 is disposed in the medium diameter part 28 of the bore, with its lower convolutions engaged against the flange 3-5 about the head 34 of the adjusting screw, and with its upper convolutions projecting into the large diameter part 29 of the bore. Adjacent its upper end, the casing 23 is formed with a pair of axially extending, diametrically opposite slots 37, that extend from the upper end of the casing 23 downwardly approximately to the lower extremity of the large diameter part 29 of the bore. Four metallic washers 38- and four plastic washers 39 are disposed in alternating arrangement in the large diameter part 29 of the bore. Each of the metallic washers 38 is formed with a pair of diametrically opposed ears 4! that are proportioned to engage in the slots 37. The lowermost of the metallic washers 38 is engaged against the upper end of the coil spring 36.

The plastic washers 39 can be made of many suitable materials, such as, for example, polyethylene, polyvinyl chloride, rubber, and the like.

The metallic washers 38 are formed with aligned circular bores 41, and the plastic washers 39 are formed with aligned hexagonal-shaped bores 42, that are aligned with each other and that are generally axially aligned with the circular bores 41 of the metallic washers 38.

A collar 43, that is formed with a bore 44, is engaged on the uppermost of the plastic washers 39, with its bore disposed coaxially with the bores of the metal washers 38. The bore 44 includes a large diameter part and a small diameter part, to provide a shoulder 46. The collar 43 is also formed with an upstanding ring-like portion 47. A washer 48 of a plastic material, such as, for example polyethylene or polytetrafiuoroethylene, is superposed upon the collar 43, and a metal washer 49 is in turn superposed on the plastic washer 48. Both the plastic washer 48 and the metallic washer 49 have large diameter bores that permit the ring-like extension 47 of the collar 43 to project therethrough.

The peripheral upper edge of the casing 23 is crimped over the uppermost washer 49, as denoted at 51, to hold the metallic washer 49 against axial movement out of the casing 23, in response to the expansive force of the spring 36.

A pin 53, that is formed with a head 54 and with a reduced diameter portion 56 to provide a shoulder portion 57, is disposed with the portion 56 frictionally engaged within the upper convolutions of a coil spring 52 and with its shoulder portion 57 engaged against the upper end of the spring 52. The reduced diameter portion 56 of the pin is formed with a reduced diameter extension 58 that depends downwardly therefrom. A sleeve 59 is disposed about the extension 58. The sleeve 59 is formed with a small diameter portion 61 that has the same diameter as the portion 56 of the pin 53. The portion 61 is frictionally engaged within the lower convolutions of the coil spring 52. The sleeve 59 is also formed with an enlarged diameter extension 62, to provide a shoulder 63, that engages against the shoulder 46 of the collar 43. A retainer 64 is staked to the lower end of the extension 58, to prevent axial movement of the Sleeve 59 relative to the pin 53. The retainer 64 is propor-tioned to fit within the bore of the coil spring 36 and to permit unrestricted movement of the spring 36 thereabout. The extension 62 is formed with axially extending plane surfaces 65 (FIG. 3) of hexagonal section, that engage in the aligned hexagonal bores 42 of the plastic washers 39, to rotate these washers upon rotation of the sleeve 59.

The head 54 of the pin 53 is formed with a transverse bore 66 (FIG. 2), and with an axially extending slot 67 the median plane of which is perpendicular to the axis of the bore 66. The lower end of the helically twisted rod 20 is disposed in the slot 67 and is secured therein by a pin 69 (-FIG. 1) that is disposed in the bore 66.

The helically twisted, ribbon-like metal rod 20- extends upwardly within the space between the confronting surfaces 17, 18, to project slightly above the top surface of the window sash 16. The strap 21 is secured to the surface 18 of the riser 12 by a pair of screws 71. The slot 22 in the strap 21 is proportioned with just sufficient clearance so that the rod 20 can pass through the slot, but the rod must rotate about its longitudinal axis in order to do so.

The bearing comprises a strap 72 that is secured to the upper surface of the window sash 16 by a pair of screws 73, and that projects outwardly over the space between the confronting surfaces '17, 18. The projecting part of strap 72 is formed with a bore, and a plastic grommet 74 is disposed in the bore. The upper end of the rod projects through the bore of the grommet 74, and the grommet acts as a bearing in which the upper end of the rod 20 is journalled.

When the window sash 16 is raised from the position shown in FIG. 1, the helically twisted rod 20 is moved upwardly and is forced through the slot 22 in the strap 21, which forces the rod 20 to rotate about its own longitudinal axis, in a clockwise direction relative to FIG. 3. As the rod 20 is rotated, it rotates the pin 53, which turns relatively freely within the coil spring 52 and the sleeve 59. The alternating metal discs or Washers 38 and plastic discs or washers 39 are maintained under an axially-directed pressure by the spring 36, and their confronting surfaces engage each other frictionally to resist relative movement. The hexagonally-shaped lower part 62 of the sleeve 59 is held against rotary movement by the plastic washers 39, in the bores of which it is engaged. Since the spring 52 is coiled about the portion 56 of the pin 53 and, as well, about the upper portion 61 of the sleeve 59, in frictional engagement with the surfaces thereof respectively, there is a slight frictional drag exerted by the spring 52. However, since this drag is in a direction that tends to uncoil the spring rather than to coil it, it is relatively small as compared with the force that is usually exerted to lift the window sash 16. The pin 53 is therefore free to rotate freely within the sleeve 59, in the clockwise direction relative to FIG. 3.

When the window sash 16 has been adjusted to the desired position, its own weight will tend to force it to return to the closed position. The weight of the window sash 16 is transmitted through the strap 24 to the clutch 19, and through the clutch to the rod 20, to tend to rotate the rod in a counterclockwise direction relative to FIG. 3. However, torque in this direction that is applied by the rod 20 to the pin 53 tends to wind the coil spring 52 tighter, causing the spring 52 to grip the surface of the portion 56 of the pin 53, and of the portion 61 of the sleeve 59, about which it is coiled, even more tightly, and there is no slippage between the coil spring 52 and the portion 61 of the sleeve 59. Therefore, torque that is applied by the rod 20 to the pin 53, in a counterclockwise direction relative to FIG. 3, is also applied to the sleeve 59; and since the sleeve 59 engages in the hexagonally shaped bores 42 of the plastic washers 39, to rotate the plastic washers 39 upon rotation of the sleeve 59, torque in this direction is resisted by the frictional engagement between the plastic washers 39 and the metallic washers 38.

The frictional engagement between the metallic washers 38 and the plastic washers 39 is controlled by the expansive force that is exerted by the coil spring 36. The compressive force that is exerted by the coil spring 36 in turn is subject to adjustment by adjustment of the position of the screw 3% in the bore 27. -For example, adjustment of the position of the screw 30 to raise the flange 35, to compress the spring 36 further, increases the force that is exerted by the spring 36 against the lowermost metallic washer 38, and increases the frictional resistance to relative movement between the metal washers 38 and the plastic washers 39. Adjustment of the screw 30 in the reverse direction decreases the frictional resistance to relative movement between these washers.

When the window is lowered, sufficient pressure is ap plied so that as the rod 20 is rotated in a counterclockwise direction relative to FIG. 3, and the sleeve 59 is rotated with the pin 53 and rod 20 by the torque that is transmitted to the sleeve 59 from the pin 53 by the coil spring 52, the frictional resistance of the clutch 19 is overcome.

As the window sash 16 is moved up and down in its frame, the annular plastic washer 26 forms a bearing between the relatively moving portions of the confronting surfaces 17, 18; and the portion of the rod 20 that is engaged in the bore of the grommet 74 cooperates With the portion of the rod that is passing through the slot 22 in the bracket 21, to hold the window sash 16 in constantly spaced relation to the riser member 12, so that the distance between the confronting surfaces 17, 18 remains constant.

Preferably, the same arrangement of the one-way clutch 19, helically twisted rod 20, bracket 21 and guide slot 22, and bearing 15, is provided at each side of the window sash 16, so that the resistance to adjustment of the window sash 16 is identical at each side of the sash. This tends to prevent jamming of the sash in its frame because of unequal resistance to movement at the opposite sides of the sash.

While this invention has been described in connection with a specific embodiment thereof, it will be understood that it is capable of further modification, and this application is intended to cover any variations, uses, or adaptations of the invention following, in general, the principles of the invention and including such departures from the present disclosure as come within known or customary practice in the art to which the invention pertains and as may be applied to the essential features hereinbefore set forth, and as fall within the scope of the invention or in the limits of the appended claims.

I claim:

1. A device for holding at an adjusted position two parts that are mounted to undergo rectilinear relative movement and that offers greater resistance to relative movement between said parts in one direction than in the other, comprising a helically twisted rod, a guide member that is rigidly secured to a first of said parts and that is formed with an aperture in which said rod is engaged to cause rotation of said rod about the longitudinal axis thereof upon relative movement between said guide member and said rod, and means securing said rod to the second of said parts and for effecting relative movement between said rod and said guide member upon relative movement of said parts and for permitting said rod to rotate about its longitudinal axis upon relative movement between said rod and said guide, said means being formed to resist rotation of said rod in one direction thereby to resist relative movement between said parts in one direction.

2. A device for holding at an adjusted position two parts that are mounted to undergo rectilinear relative movement and that offers greater resistance to relative movement between said parts in one direction than in the other, comprising a helically twisted rod, a guide member that is rigidly secured to a first of said parts and that is formed with an aperture in which said rod is engaged to cause rotation of said rod about the longitudinal axis thereof upon lengthwise movement between said rod and said guide member, and friction clutch means securing said rod to said second part for rectilinear relative movement between said rod and said guide member upon relative movement between said parts to effect rotary movement of said rod about its longitudinally extending axis upon relative movement between said parts, said clutch being disposed to resist rotation of said rod in one direction thereby to resist relative movement between said parts in one direction.

3. A device for holding at an adjusted position two parts that are mounted to undergo rectilinear relative movement and that offers greater resistance to relative movement between said parts in one direction than in the other, comprising a helically twisted ribbon-like rod, a guide member that is rigidly secured to a first of said parts and that is formed with a slot in which said rod is engaged, friction clutch means securing said rod to said second part for rectilinear relative movement between said slot and said rod upon relative movement between said parts to effect rotary movement of said rod about its longitudinally extending axis upon relative movement between said parts, said clutch means being disposed to resist rotation of said rod in one direction thereby to resist relative movement between said parts in one direction by exerting a frictional drag thereon, and means for adjusting said frictional drag to a preselected value.

4. A coupling between a drive shaft and a driven shaft that is operative to permit said shafts to undergo independent relative rotary movement in one direction of rotation of said drive shaft and to cause said shafts to rotate together as a unit in the other direction of rotation of said drive shaft, comprising a coil spring that has one group of convolutions frictionally engaged about said drive shaft and a second group of convolutions frictionally engaged about said driven shaft, means intermediate said shafts for preventing axial movement between said shafts and means attached to said driven shaft for preventing said driven shaft from turning when said drive shaft is turned in a direction tending to unwind said coil spring and for permitting the friction created by said coil spring when being wound by said drive shaft to turn said driven shaft.

5. A one-way friction clutch comprising a first shaft that is mounted for rotation within a casing, a series of engaged discs attached alternately to said shaft and said casing and mounted to provide frictional resistance to relative rotation between said shaft and said casing, a drive shaft coaxial with said first shaft, and a coil spring that has one group of convolutions frictionally engaged about one of said shafts and a second group of convolutions frictionally engaged about the other of said shafts.

6. A one-way friction clutch comprising a first shaft that is mounted for rotation within a casing and for limited axial movement relative to said casing, a series of engaged discs attached alternately to said shaft and said casing and mounted for limited axial movement relative to said casing and to provide frictional resistance to relative rotation between said shaft and said casing, a drive shaft coaxial with said first shaft, a coil spring that has one group of convolutions frictionally engaged about said first shaft and a second group of convolutions frictionally engaged about said drive shaft, spring means interposed between said casing and one of said discs constantly to urge said discs in one axial direction within said casing, and means to adjust the pressure that is exerted by said spring means on said discs thereby to adjust the frictional resistance to relative rotation between said first shaft and said casing.

7. A device for holding at an adjusted position two parts that are mounted to undergo rectilinear relative movement and that offers greater resistance to r'elative movement between said parts in one direction than in the other, comprising a helically twisted rod, a guide member that is rigidly secured to a first of said parts and that is formed with an aperture in which said rod is engaged to cause rotation of said rod about the longitudinal axis thereof upon lengthwise relative movement between said rod and said guide member, a one-way friction clutch interposed between the second of said parts and said rod, said clutch comprising a first shaft that is mounted for rotation within a casing, a series of engaged discs attached alternately to said shaft and said casing and mounted to provide frictional resistance to relative rotation between said shaft and said casing, a second shaft coaxial with said first shaft, a coil spring that has one group of convolutions frictionally engaged about one shaft and a second group of convolutions frictionally engaged about said second shaft, said rod being secured at one of its ends to said second shaft, to effect rotary movement of said rod about its longitudinally extending axis upon relative movement between said parts, said clutch being disposed to resist r0- tation of said rod in one direction thereby to resist relative movement between said parts in one direction.

8. A device for holding at an adjusted position two parts that are mounted to undergo rectilinear relative movement and that offers greater resistance to relative movement between said parts in one direction than in the other, comprising a helically twisted rod, a guide member that is rigidly secured to a first of said parts and that is formed with an aperture in which said rod is engaged to cause rotation of said rod about the longitudinal axis thereof upon relative movement between said rod and said guide member lengthwise of said rod, friction clutch means securing one end of said rod to said second part for said relative movement between said rod and said guide member upon relative movement between said parts to effect rotary movement of said rod about a longitudinal axis on relative movement between said parts, said clutch being disposed to resist rotation of said rod in one direction thereby to resist relative movement between parts in one direction, said friction clutch means comprising a first shaft that is mounted for rotation within a casing and for limited axial movement relative to said casing, a series of engaged discs that are attached alternately to said shaft and said casing and mounted for limited axial movement relative to said casing and to provide frictional resistance to relative rotation between said shaft and said casing, a second shaft coaxial with said first shaft, a coil spring that has one group of convolutions frictionally engaged about one of said shafts and a second group of convolutions frictionally engaged about the other of said shafts, spring means interposed between said casing and one of said discs constantly to urge said discs in one axial direction within said casing, and means to adjust the pressure that is exerted by said spring means on said discs thereby to adjust said frictional resistance.

9. A friction brake spiral balance adapted for use with a Window sash part and a frame part in which said sash part is movable, and said frame part being proportioned to have a space between the lateral face of the sash part and the confronting surface of the frame part, said balance comprising a guide member mounted on a first of said parts and a bearing member and a rod mounted on the second of said parts in spaced relation to each other, said rod being engaged by said guide member and being rotated thereby upon relative movement between said parts, means for resisting relative movement between said rod and said guide member at least in one direction thereby to resist relative movement between said parts in one 30 direction, one portion of said rod being engaged with and aligned by said bearing member to cooperate with said guide member to guide the relative movement between said parts, and bearing means mounted adjacent the other end of said nod engaging the confronting faces of said parts to hold said parts in spaced relation and further to guide relative movement between said parts.

10. A friction brake spiral balance adapted for use with a window sash part and a frame part in which said sash part is movable, and said frame part being proportioned to have a space between the lateral face of the sash part and the confronting surface of the frame part, said balance comprising a helically twisted ribbon-like rod that is disposed in said space, a guide member secured to said frame part and formed with a slot in which said rod is engaged to effect rotary movement of said rod about a longitudinal axis thereof upon lengthwise movement thereof through said slot, friction clutch means including a casing that is secured to said sash part and that is formed with a bearing part that is disposed to engage said confronting faces to hold said parts in spaced relation relative to each other, one end of said rod being operatively connected to said clutch means, said clutch being disposed to resist rotation of said rod in one direction of rotation thereof thereby to resist relative movement between said parts in one direction by exerting a frictional drag thereon, and bearing means secured to said window part remote from said casing, the other end of said rod being journ alled in said bearing means and being held thereby and by said friction clutch at a constant distance from said window part.

References Cited in the file of this patent UNITED STATES PATENTS 2,598,560 Kenyon May 27, 1952 2,890,480 Gregg et al. June 16, 1959 2,904,819 Seaman Sept. 22, 1959 

